The present invention relates to an endoscope having an operation section which has been structurally improved, thereby facilitating assembly of the endoscope.
The operation section of a prior art endoscope is assembled in such a way that, as shown in FIG. 1, a pair of covering members b are screwed and fastened by means of, e.g., setscrews, to a base member a serving as a main body of said operation section, from the right and left sides thereof, respectively. In this case, however, the base member a is designed to have sufficient mechanical strength and the covering members b are intended to function only as a casing attached to the base member a.
However, the base member a within the operation section has disposed therearound a plurality of built-in members c, such as a bending operation wire, a treating instrument inductor raising wire, an air/water intake tube, various channels, an electrical wire distribution, etc. Moreover, within the operation section having such a base member, the elements extended into the side of the endoscope whose base member has an insertion portion must be connected to the elements extended from the side of an ocular portion or from the side of a connector portion connected to accessory devices. For this reason, it is impossible to construct the base member a in such a way that its structure may entail a large section modulus to house the built-in members. At best only a structure such as that shown in FIG. 1, having a sectional configuration shaped like the letter I, may be adopted for the base member.
Accordingly, it was necessary to make the operation section large, both in weight and thickness, to ensure sufficient mechanical strength to resist compression and bending forces. In other words, the prior art endoscope was unsatisfactory as an endoscope which might be operated over long periods, even with one hand.